| Background: Sevoflurane is a new volatile agent with desirable clinical properties, such as low blood-gas partition coefficient (λB/G)of 0.65, potent, pleasant odor and hence rapid induction and recovery, lack of cardiac arrhythmias when administered epmephrine, lack of airway irritability etc. In some clinical situations, because cardiovascular properties of the anesthetic are a significant determinant factors of cardiovascular responses, an understanding of these properties enables the anesthesiologists to anticipate possible cardiovascular responses.Objective: to evaluate the hemodynamic changes of elderly patients with coronary artery disease(CHD) undergoing non-cardiac surgery during sevoflurane,or, mixture of sevoflurane with nitrous oxide(N2O) inhaled induction so as to found both safe and effective method of inhaled induction.Methods: seventy-five ASA II-III patients were divided into five groups randomly. In group I ,patients was inhaled 5%sevoflurane with 100% O2, group II 5%sevoflurane and N2O:O2=2:1, groupIII 7% sevoflurane with 100% O2, group IV7% sevoflurane and N2O:O2 =2:1 after midazolam and fentanyl intravenously. Anesthesia was induced and maintained by inhalation of the designated anesthetics. In control group(group V), patients were received 1.21.5mg/kg propofol intravenously during induction. Hemodynamic measurements were performed with Bioz.com system which is the noninvasive hemodynamic and cardiac function monitoring system. Patients' airway were facilities with LMA-Proseal? until the end expiratory concentration of sevoflurane reached to 1.5MAC (2.6%) and maintained with 0.8%1.5% sevoflurane-50% N2O. Heart rate (HR), systolicpressure(SBP) -. Diastolic pressure(DBP)> mean artery pressure(MAP)^ Cardiac Output(CO^ Cardiac index(CI)> Stroke Volume (SV)> Stroke Index(SI>N systemic vascular resistance(SVR)^ systemic vascular resistance index(SVRI)> Thoracic fluid content(TFC)> Acceleration index(ACI)> Systolic time ratio(STR)^ Left cardiac work (LCW)> Left cardiac work index(LCWI)> product of heart rate and systolic pressure(RPP) were recorded and analyzed statistically.Result: At the beginning of anesthesia, the hemodynamic parameters of patients in each group could be compared with other group. Similar to other volatile anesthetics, dose-dependent decrease in SI^ DBP^ MAP and HR occurred during sevoflurane anesthesia, but those changes could be managed by altering inspired concentration. MAP decreased significantly (p<0.05) and persistently in group I n IIL IV except in II group and propofol groups. Bradycardia requiring anticholinergic treatment because of associated hypotension had been reported in some patients when 7% sevoflurane or propofol was used for induction. ACL CO n CL SV\ SI were consistently lower in five groups, but III sevoflurane were associated with significantly lower incidences of CO and CI than other groups at 1 -. 3> 5 minute afterinserted LMA-Proseal?(p<0.05). Decrease in SVTU SVRI after induction of anesthesia in group I > II > IIK IV were similar, whereas a tendency toward persistent increase in SVR% SVRI -, STR has been noted during propofol induction anesthesia. Thoracic Fluid Content was unchanged from baseline with either agent. The average baseline 6.2-7.0 kgm of LCW and 3.6-4.1 kgm"1 of LCWI decrease with value lower than the critical threshold LCW and LCWI in I % UK IV groups. The product of heart rate and systolic pressure in III group were significantly lower than any other four groups (p<0.05).Conclusion: The induction courses were rather smooth during induction with 5% sevoflurane and 5% sevoflurane with 67% N2O. Anesthesia induction with sevoflurane or sevoflurane with N2O:O2=2:1 inhalation has slight effect on thehemodynamic factors compared with propofol in elder patients undergoing non-cardiac surgery. Inhalation with 67% nitrous oxide can keep the stability of cardiovascular system and it is a valid method on the elder patients with cardiac ischemia disease.
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